@tridge Thank you for looking through the log. I really should buy new batteries. Perhaps I should have bought them earlier, to avoid this hard touch and go. I also got a bit to confident and let the descent rate get to high.
Thanks for yor reply. A lot of what I have read about your Mozzies inspired me to build my Quadplane. I just could not bring myself to use racecopter motors for lift. It just looks to cool hovering around.
So the lift motors are Tiger Motor MN2213 950kv (the anniversary bundle) running on 4s
with 9x5x3 Graupner E-Props.
ESCs are Flycolor 30A with blheli.
The motors get warm, but not to hot to touch after 5min of hover.
My neighbour borrowed my infrared thermometer to check on his bees, so no hard numbers right now
I had it setup as X quad at first, but it was totally uncontrollable in yaw, so I changed to H quad. Yaw control is still weak, though. It also wants to yaw left on take off and right after transitioning back to hover. I checked the motor alignment and all seems straight on the bench. Perhaps there is something going on under load. I will tie the MT down and run the motors to check this.
I mounted the motors inverted for two reasons:
1. The tips of the rear props run under the wing. From tilting the thrust angle forward (motors backwards in my case) like you suggested, the distance between prop and wing gets bigger this way, while it would get smaller, with the prop over the wing.
2. The plywood motor arms are 35mm wide and I wanted to avoid loosing the thrust and causing vibrations, by blasting the propwash onto the arms.
The drawback is the low ground clearance of the props, especially at the front.
I will order new batteries and try again.